CN105316578A - Automobile beam steel which is low in carbon equivalent, easy to weld and more than 750Mpa in yield strength and fabrication method thereof - Google Patents
Automobile beam steel which is low in carbon equivalent, easy to weld and more than 750Mpa in yield strength and fabrication method thereof Download PDFInfo
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Abstract
The invention relates to automobile beam steel which is low in carbon equivalent, easy to weld and more than 750Mpa in yield strength and a fabrication method thereof. The steel is composed of, by weight, 0.03%-0.05% of C, 0.06-0.15% of Si, 1.80%-1.85% of Mn, 0.010%-0.015% of P, 0.001%-0.003% of S, 0.065%-0.085% of Nb, 0.12%-0.18% of Mo, 0.15%-0.16% of Ti, 0.0015%-0.0045% of Ca, 0.02%-0.05% of Al and the balance Fe and unavoidable impurities. The method includes steel making, continuous casting, heating, hot continuous rolling, laminar cooling, coiling, slow cooling and finishing. High strength and high tenacity of the automobile beam steel can be guaranteed, meanwhile, low-cost welding wires can be used, and the problems of segregation and surface qualities are avoided.
Description
Technical field
The present invention relates to a kind of beam steel and manufacture method thereof, the beam steel of easy more than the welding buckling strength 750Mpa of especially a kind of low-carbon-equivalent and manufacture method thereof.
Background technology
According to the applicant understood, along with the fast development of domestic heavy-duty car industry, automobile production producer to the performance of automobile structure steel and quality requirements also more and more higher.
At present, the yield strength commonly using steel for automobile crossbeam is 500Mpa rank, tensile strength is 550Mpa rank.If the yield strength of steel for automobile crossbeam can reach more than 750Mpa and tensile strength can reach more than 780Mpa, then can reduce steel plate thickness, and guarantee that weight-carrying capacity is constant and even increase.Meanwhile, if its carbon equivalent Ceq (International Welding association criterion=C+Mn/6+ (Cu+Ni)/15+ (Cr+Mo+V)/5) can control below 0.41, then welding process can adopt low cost welding wire: namely adopt 500Mpa level welding wire.General 750Mpa rank steel must adopt 750Mpa level welding wire, but 750Mpa level welding wire price is approximately high 10000 yuan/ton than 500Mpa level steel welding wire price.The steel for automobile crossbeam that above-mentioned two (high-strength, low-carbon-equivalents) require can be met if can develop, then can realize alleviating light weight, fall this, save energy and reduce the cost, meet society energy-saving and environmental protection, green theme.
Find through retrieval, the Chinese invention patent application of application number 201110156739.8 application publication number CN102226249A discloses high tensile hot rolled steel sheet of a kind of cold shaping excellent property and preparation method thereof, this steel plate yield strength is 750-810MPa, and tensile strength is 850-882MPa.
But there is following disadvantage in this patent application: (1) also reckons without the problem adopting low cost welding wire, contains Ceq and is greater than 0.41, cannot uses the technical scheme of low cost welding wire; This can cause its steel grades and preparation method not to be optimized to only for the degree of Ceq below 0.41 simultaneously.(2) Si content is 0.15-0.30%, because Si generates sharp brilliant peridotites (Fe in hot rolling heat-processed
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4), rust red iron scale can be produced when Si content is more than 0.2%, cannot be removed by hot rolling de-scaling operation, not only affect plate surface quality, and easily cause steel plate get rusty perforation and japanning performance reduce, affect product military service process safety and surface quality.(3) Mn content is 1.2-1.9%, when Mn content is greater than 1.85%, Mn segregation (as shown in Figure 1) is easily there is in steel at casting process, for the high-strength steel of yield strength in 750Mpa rank, the Mn of casting process is segregated in course of hot rolling and cannot eliminates completely, easily cause military service process to lose efficacy from segregation, cause security incident.(4) section cooling speed >=60 DEG C after finish rolling/S, its cooling rate requires to exceed section cooling general ability, and need special equipment to realize, this obviously can limit its scope of application.
The Chinese invention patent application of application number 201110282100.4 application publication number CN103014494A discloses a kind of automotive frame hot-rolled steel sheet and manufacture method thereof, and this steel plate yield strength is 710-770MPa, and tensile strength is 780-850MPa.
But there is following disadvantage in this patent application: (1) steel plate yield strength non-fully is in more than 750MPa, performance Shortcomings.(2) contain Ceq to be equally greater than 0.41, the technical scheme of low cost welding wire cannot be used, and cause its steel grades and preparation method not to be optimized to only for the degree of Ceq below 0.41.(3) Si content is 0.15-0.35%, the problem produced when there is Si content equally more than 0.2%.(4) Mn content is 1-2%, there is the problem produced when Mn content is greater than 1.85% equally.(5) type of cooling is that after first rapid cooling, layer is cold, is unfavorable for Simplified flowsheet, reduces costs.
Because heavy-duty car requires more and more higher to load-carrying, automobile manufacturing enterprise is brought up to 750Mpa to automotive frame intensity rank and is required more and more urgent, and the problem simultaneously bringing weldability, processability to decline due to the raising of intensity rank also requires to solve simultaneously.In addition, automobile industry Market competition, any measure that can reduce costs, be all that Automobile Enterprises is welcome, low-carbon-equivalent of the present invention easily welds high-strength, high-ductility steel plate and should require and develop by this kind just.
Summary of the invention
Technical problem to be solved by this invention is: overcome prior art Problems existing, the beam steel of easy more than the welding buckling strength 750Mpa of a kind of low-carbon-equivalent is provided, while guaranteeing high-strength and high ductility, guarantee to use low cost welding wire, and segregation and surface quality problems can not occur.In addition, corresponding manufacture method is also provided.
The technical scheme that the present invention solves its technical problem is as follows:
The beam steel of easy more than the welding buckling strength 750Mpa of a kind of low-carbon-equivalent, it is characterized in that, be made up of by weight percentage following chemical composition: 0.03 ~ 0.05% C, 0.06 ~ 0.15% Si, 1.80 ~ 1.85% Mn, 0.010 ~ 0.015% P, 0.001 ~ 0.003% S, 0.065 ~ 0.085 Nb, 0.12 ~ 0.18% Mo, 0.15 ~ 0.16% Ti, 0.0015 ~ 0.0045% Ca, 0.02 ~ 0.05% Alt, surplus is Fe and inevitable impurity; Carbon equivalent Ceq IIW=C+Mn/6+ (Cr+Mo+V)/5+ (Cu+Ni)/15, the Ceq IIW of described beam steel is 0.354 ~ 0.394, yield strength >=750Mpa, tensile strength is 780 ~ 950Mpa, elongation after fracture >=15%.
The present invention also provides:
A manufacture method for the above beam steel of low-carbon-equivalent easy welding buckling strength 750Mpa, typical process flow is steel smelting-continuous casting-heating-hot continuous rolling-section cooling-batch-slow cooling-finished product; It is characterized in that,
In described steel making working procedure: adopt oxygen top and bottom combined blown converter smelting molten steel, tapping temperature is 1645 DEG C ~ 1665 DEG C, and gained molten steel contains the composition of following weight percent: 0.015 ~ 0.05% C, 0.001 ~ 0.003% S, 0.010 ~ 0.015% P, then, converter gained molten steel is put in ladle refining furnace and carries out the refining of LF stove, at the end of refining, liquid steel temperature is 1580 DEG C ~ 1630 DEG C, and gained molten steel contains the composition of following weight percent: 0.03% ~ 0.05% C, 0.06% ~ 0.15% Si, 1.80% ~ 1.85% Mn, 0.010 ~ 0.015% P, 0.001 ~ 0.003% S, 0.065% ~ 0.085 Nb, 0.02% ~ 0.05% Alt, afterwards, LF refining gained molten steel is carried out RH vacuum-treat, carry out trimming, and calcium line is fed at the end of vacuum-treat, at the end of RH vacuum-treat, liquid steel temperature is: 1580 DEG C ~ 1620 DEG C, gained molten steel is grouped into by the one-tenth of following weight percent: 0.03 ~ 0.05% C, 0.06 ~ 0.15% Si, 1.80 ~ 1.85% Mn, 0.010 ~ 0.015% P, 0.001 ~ 0.003% S, 0.065 ~ 0.085% Nb, 0.12 ~ 0.18% Mo, 0.15 ~ 0.16% Ti, 0.0015 ~ 0.0045% Ca, 0.02 ~ 0.05% Alt, surplus is Fe and inevitable impurity,
In described continuous casting working procedure, adopt overall argon gas-sealed to cast, molten steel injects tundish by the slide gate nozzle of ladle bottom, and tundish temperature is 1534 DEG C ~ 1554 DEG C; Adopt funnel-type crystallizer, Casting speed is 0.7 ~ 0.9m/min, and the slab thickness going out crystallizer is 230mm;
In described heating process, strand is delivered to process furnace, strand charging temperature is 800 DEG C ~ 1000 DEG C, and tapping temperature is 1240 DEG C ~ 1270 DEG C, and heat-up time is 180 ~ 240min;
In described hot continuous rolling operation, first strand after heating is put reversible roughing mills and carry out roughing, it is 1055 DEG C ~ 1085 DEG C that roughing temperature out controls, and after roughing, workpiece thickness is 45mm or 49mm; Intermediate blank is put seven frame tandem mill groups again and carry out finish rolling, entry temperature at finishing is 1015 DEG C ~ 1045 DEG C, and exit temperature at finishing is 810 DEG C ~ 850 DEG C, and after finish rolling, the thickness of coiled sheet is 4.0mm ~ 10.0mm;
In described section cooling operation, speed of cooling is 35 DEG C/more than s;
In described coiling process, adopt reeling machine to coil into coil of strip, coiling temperature is 550 DEG C ~ 590 DEG C;
In described slow cooling operation, coil of strip to be put in burial pit cooling or adopt cooling in heap mode to cool, controlled cooling model speed≤10 DEG C/h;
The Ceq IIW of described finished product is 0.354 ~ 0.394, yield strength >=750Mpa, and tensile strength is 780 ~ 950Mpa, elongation after fracture >=15%.
The technical scheme that the inventive method is perfect is further as follows:
Preferably, in described steel making working procedure, the composition containing following weight percent in converter gained molten steel: 0.015 ~ 0.04% C, 0.001 ~ 0.003% S, 0.010 ~ 0.015% P; LF refining gained molten steel contains the composition of following weight percent: 0.03% ~ 0.05% C, 0.06% ~ 0.15% Si, 1.80% ~ 1.85% Mn, 0.010 ~ 0.015% P, 0.001 ~ 0.003% S, 0.065% ~ 0.085 Nb, 0.12 ~ 0.18% Mo, 0.10 ~ 0.12% Ti, 0.02% ~ 0.05% Alt.
Preferably, in described continuous casting working procedure, tundish temperature is 1535 DEG C ~ 1550 DEG C, and Casting speed is 0.7 ~ 0.8m/min.
Preferably, in described heating process, tapping temperature is 1245 DEG C ~ 1265 DEG C, and heat-up time is 190 ~ 240min.
Preferably, in described hot continuous rolling operation, it is 1065 DEG C ~ 1085 DEG C that roughing temperature out controls; Entry temperature at finishing is 1020 DEG C ~ 1040 DEG C, and exit temperature at finishing is 820 DEG C ~ 840 DEG C, and after finish rolling, the thickness of coiled sheet is 6.0mm ~ 10.0mm.
Preferably, in described section cooling operation, adopting leading portion cooling and the total length type of cooling, speed of cooling is 35 DEG C/s ~ 60 DEG C/s (general hot rolling mill section cooling ability can be met like this, applied widely); In described coiling process, coiling temperature is 560 DEG C ~ 580 DEG C.
Preferably, in described steel making working procedure, RH vacuum-treat gained molten steel is grouped into by the one-tenth of following weight percent: 0.03% C, 0.08% Si, 1.80% Mn, 0.012% P, 0.003% S, 0.080% Nb, 0.12% Mo, 0.15% Ti, 0.0018% Ca, 0.034% Alt, and surplus is Fe and inevitable impurity; In described heating process, tapping temperature is 1255 DEG C; In described hot continuous rolling operation, exit temperature at finishing is 830 DEG C; In described section cooling operation, speed of cooling is 35 DEG C/s; In described coiling process, coiling temperature is 580 DEG C; The Ceq IIW of described finished product is 0.354, and yield strength is 780Mpa, and tensile strength is 850Mpa, and elongation after fracture is 19%.
Preferably, in described steel making working procedure, RH vacuum-treat gained molten steel is grouped into by the one-tenth of following weight percent: 0.045% C, 0.11% Si, 1.82% Mn, 0.011% P, 0.0028% S, 0.075% Nb, 0.15% Mo, 0.155% Ti, 0.0025% Ca, 0.040% Alt, and surplus is Fe and inevitable impurity; In described heating process, tapping temperature is 1245 DEG C; In described hot continuous rolling operation, exit temperature at finishing is 840 DEG C; In described section cooling operation, speed of cooling is 45 DEG C/s; In described coiling process, coiling temperature is 565 DEG C; The Ceq IIW of described finished product is 0.378, and yield strength is 775Mpa, and tensile strength is 840Mpa, and elongation after fracture is 18%.
Preferably, in described steel making working procedure, RH vacuum-treat gained molten steel is grouped into by the one-tenth of following weight percent: 0.05% C, 0.14% Si, 1.85% Mn, 0.013% P, 0.0025% S, 0.071% Nb, 0.18% Mo, 0.16% Ti, 0.0035% Ca, 0.038% Alt, and surplus is Fe and inevitable impurity; In described heating process, tapping temperature is 1240 DEG C; In described hot continuous rolling operation, exit temperature at finishing is 825 DEG C; In described section cooling operation, speed of cooling is 60 DEG C/s; In described coiling process, coiling temperature is 560 DEG C; The Ceq IIW of described finished product is 0.394, and yield strength is 840Mpa, and tensile strength is 915Mpa, and elongation after fracture is 17%.
The effect of the present invention's each composition used is as follows:
C: carbon is the principal element of the obdurability affecting beam steel, C% increase can improve intensity, but reduces toughness, in the present invention controls C 0.03 ~ 0.05%.
Si: silicon can improve product strength, but consider the requirement of user vehicle Surface Quality, it is 0.06-0.15% that the present invention designs Si content, can realize the balance of intensity and surface quality;
Mn: manganese is the elementary sum alloying element of automotive frame Hi-Stren steel.In the present invention, Mn is controlled 1.80 ~ 1.85%, to improve yield strength.
P, S:P easily bring segregation and worsen the disadvantageous effect of toughness in automobile structural steel, and P can cause steel " cold short ".S easily forms MnS with Mn and is mingled with, and the toughness of reduction steel, reduce wide clod wash qualification rate, S can cause " hot-short ".Therefore reduce P, S content in Hi-grade steel beam steel as far as possible.In the present invention, P controls to control≤0.003% at≤0.015%, S.
Ca: calcium can be combined with sulphur and reduce banded structure rank, separately can realize inclusion modification and make inclusion balling, be uniformly distributed inclusion, meets the requirement of beam steel military service process high fatigue characteristic.In the present invention, Ca controls 0.0015 ~ 0.0045%.
Mo: molybdenum is the important element of high-strength beam steel steel, the main characteristic playing its postponement perlitic transformation, plays phase transformation strengthening effect.In the present invention, Mo controls 0.12 ~ 0.18%.
Nb: niobium is the main micro alloying element of low-alloy high-strength steel for automobile crossbeam, mainly plays refined crystalline strengthening effect.Nb can significantly improve the recrystallization temperature Tnr of steel on the one hand, the gross distortion of course of hot rolling is made to be able to carrying out lower than its below recrystallization temperature Tnr, thus obtain tiny, containing a large amount of deformation bands austenite structure, the austenite structure before phase transformation is tried one's best refinement; Nb (C, N) tiny in controlled cooling model process separates out in controlled rolling and controlled cooling process on the other hand, plays precipitation strength effect, improves the intensity of steel.In the present invention, Nb controls: 0.065 ~ 0.085%.
Ti:Ti is in low-carbon micro steel-alloy, and adding Ti can crystal grain thinning and precipitation strength, can improve yield strength and the toughness of steel.Main and the Ti of the improvement of this performance can improve austenite recrystallization temperature and austenite Coarsening Temperature, thus it is relevant with grain size in heat-processed to improve continuous casting, Ti adds the precipitation incubation period that can extend NbC in Nb steel simultaneously, the precipitation time opening making the carbide in Nb-Ti clad steel is evening in Nb steel comparatively, thus makes that precipitate is more tiny, disperse.Due to Ti at high temperature, TiN high temperature refractory particle can be formed with N, therefore Ti add the grain fineness number that can also improve welded heat affecting zone, thus improve the toughness of welded heat affecting zone.In the present invention, Ti controls 0.15 ~ 0.16%.
Technical conceive of the present invention is as follows:
It is 750Mpa that the present invention designs the yield strength of steel grade minimum, ordinary method generally realizes by improving C, Mn content, and the present invention needs carbon equivalent Ceq IIW to control below 0.41, therefore, first, it is 1.80-1.85% that the present invention designs Mn content, while keeping compared with high Mn content, avoids Mn segregation occurs as far as possible; Lower C content is adopted effectively to reduce carbon equivalent Ceq IIW; Meanwhile, add the Ca of 0.0015 ~ 0.0045% to improve segregation and to improve inclusion shape, and greatly improve the fatigue property under the effect of automotive frame military service process repeated load.(as shown in Figure 2, the basic segregation-free of the present invention.)
Secondly, the present invention adopts does not have influential alloy element Nb and Ti to strengthen steel to carbon equivalent, Nb and Ti is combined with C to produce carbide to realize and strengthens, play carefully crystalline substance and act in hot-rolled product.Play a role in the operation of rolling for making the microalloy element added, heat must be designed and make the first solid solution of microalloy element, therefore heating process reasonable in design is needed to make the carbide of Nb and Ti in the abundant solid solution of heating, and adopt slow cooling to cool the technique that Nb and Ti carbide is fully separated out in the hot rolling reeling stage, realize the high strength realizing steel on the basis ensureing low-carbon-equivalent.
Finally, contriver, after going deep into practical studies, has drawn and the manufacturing process that steel grades of the present invention matches, and successfully can obtain low-carbon-equivalent and easily weld and the beam steel of high-strength and high ductility.(TiN, Ti (CN) of finished product of the present invention, Nb (CN) Dispersed precipitate are as shown in Figure 3, Figure 4.)
Beneficial effect of the present invention is as follows: the Ceq IIW of beam steel is 0.354 ~ 0.394 yield strength >=750Mpa, and tensile strength is 780 ~ 950Mpa, elongation after fracture >=15%, cold-bending property b=35mm, bending radius d=2.0a.While guaranteeing high-strength and high ductility, guarantee to use low cost welding wire, and segregation and surface quality problems can not occur.
Accompanying drawing explanation
Fig. 1 is the Mn segregation schematic diagram that background technology is mentioned.
Fig. 2 is the basic segregation-free schematic diagram of the present invention.
Fig. 3, Fig. 4 are TiN, Ti (CN), Nb (CN) the Dispersed precipitate schematic diagram of finished product of the present invention.
Embodiment
With 3 embodiments, the present invention is described in further detail below.But the invention is not restricted to given example.
The typical process flow of employing steel smelting-continuous casting-heating-hot continuous rolling-section cooling-batch-slow cooling-finished product.
In each embodiment, the component of steel making working procedure RH vacuum-treat gained molten steel is as shown in table 1, main technologic parameters and performance test result as shown in table 2.
Table 1 composition (Wt%)
The surplus noting each embodiment is Fe and inevitable impurity.
Table 2 main technologic parameters and performance test result
Note cold bending experiment d=1a and d=0.5a detects, and result is qualified.
In addition to the implementation, the present invention can also have other embodiments.All employings are equal to the technical scheme of replacement or equivalent transformation formation, all drop on the protection domain of application claims.
Claims (10)
1. the beam steel of easy more than the welding buckling strength 750Mpa of low-carbon-equivalent, it is characterized in that, be made up of by weight percentage following chemical composition: 0.03 ~ 0.05% C, 0.06 ~ 0.15% Si, 1.80 ~ 1.85% Mn, 0.010 ~ 0.015% P, 0.001 ~ 0.003% S, 0.065 ~ 0.085 Nb, 0.12 ~ 0.18% Mo, 0.15 ~ 0.16% Ti, 0.0015 ~ 0.0045% Ca, 0.02 ~ 0.05% Alt, surplus is Fe and inevitable impurity; Carbon equivalent Ceq IIW=C+Mn/6+ (Cr+Mo+V)/5+ (Cu+Ni)/15, the Ceq IIW of described beam steel is 0.354 ~ 0.394, yield strength >=750Mpa, tensile strength is 780 ~ 950Mpa, elongation after fracture >=15%.
2. a manufacture method for the above beam steel of low-carbon-equivalent easy welding buckling strength 750Mpa, typical process flow is steel smelting-continuous casting-heating-hot continuous rolling-section cooling-batch-slow cooling-finished product; It is characterized in that,
In described steel making working procedure: adopt oxygen top and bottom combined blown converter smelting molten steel, tapping temperature is 1645 DEG C ~ 1665 DEG C, and gained molten steel contains the composition of following weight percent: 0.015 ~ 0.05% C, 0.001 ~ 0.003% S, 0.010 ~ 0.015% P, then, converter gained molten steel is put in ladle refining furnace and carries out the refining of LF stove, at the end of refining, liquid steel temperature is 1580 DEG C ~ 1630 DEG C, and gained molten steel contains the composition of following weight percent: 0.03% ~ 0.05% C, 0.06% ~ 0.15% Si, 1.80% ~ 1.85% Mn, 0.010 ~ 0.015% P, 0.001 ~ 0.003% S, 0.065% ~ 0.085 Nb, 0.02% ~ 0.05% Alt, afterwards, LF refining gained molten steel is carried out RH vacuum-treat, carry out trimming, and calcium line is fed at the end of vacuum-treat, at the end of RH vacuum-treat, liquid steel temperature is: 1580 DEG C ~ 1620 DEG C, gained molten steel is grouped into by the one-tenth of following weight percent: 0.03 ~ 0.05% C, 0.06 ~ 0.15% Si, 1.80 ~ 1.85% Mn, 0.010 ~ 0.015% P, 0.001 ~ 0.003% S, 0.065 ~ 0.085% Nb, 0.12 ~ 0.18% Mo, 0.15 ~ 0.16% Ti, 0.0015 ~ 0.0045% Ca, 0.02 ~ 0.05% Alt, surplus is Fe and inevitable impurity,
In described continuous casting working procedure, adopt overall argon gas-sealed to cast, molten steel injects tundish by the slide gate nozzle of ladle bottom, and tundish temperature is 1534 DEG C ~ 1554 DEG C; Adopt funnel-type crystallizer, Casting speed is 0.7 ~ 0.9m/min, and the slab thickness going out crystallizer is 230mm;
In described heating process, strand is delivered to process furnace, strand charging temperature is 800 DEG C ~ 1000 DEG C, and tapping temperature is 1240 DEG C ~ 1270 DEG C, and heat-up time is 180 ~ 240min;
In described hot continuous rolling operation, first strand after heating is put reversible roughing mills and carry out roughing, it is 1055 DEG C ~ 1085 DEG C that roughing temperature out controls, and after roughing, workpiece thickness is 45mm or 49mm; Intermediate blank is put seven frame tandem mill groups again and carry out finish rolling, entry temperature at finishing is 1015 DEG C ~ 1045 DEG C, and exit temperature at finishing is 810 DEG C ~ 850 DEG C, and after finish rolling, the thickness of coiled sheet is 4.0mm ~ 10.0mm;
In described section cooling operation, speed of cooling is 35 DEG C/more than s;
In described coiling process, adopt reeling machine to coil into coil of strip, coiling temperature is 550 DEG C ~ 590 DEG C;
In described slow cooling operation, coil of strip to be put in burial pit cooling or adopt cooling in heap mode to cool, controlled cooling model speed≤10 DEG C/h;
The Ceq IIW of described finished product is 0.354 ~ 0.394, yield strength >=750Mpa, and tensile strength is 780 ~ 950Mpa, elongation after fracture >=15%.
3. manufacture method according to claim 2, is characterized in that, in described steel making working procedure, and the composition containing following weight percent in converter gained molten steel: 0.015 ~ 0.04% C, 0.001 ~ 0.003% S, 0.010 ~ 0.015% P; LF refining gained molten steel contains the composition of following weight percent: 0.03% ~ 0.05% C, 0.06% ~ 0.15% Si, 1.80% ~ 1.85% Mn, 0.010 ~ 0.015% P, 0.001 ~ 0.003% S, 0.065% ~ 0.085 Nb, 0.12 ~ 0.18% Mo, 0.10 ~ 0.12% Ti, 0.02% ~ 0.05% Alt.
4. manufacture method according to claim 3, it is characterized in that, in described continuous casting working procedure, tundish temperature is 1535 DEG C ~ 1550 DEG C, and Casting speed is 0.7 ~ 0.8m/min.
5. manufacture method according to claim 4, it is characterized in that, in described heating process, tapping temperature is 1245 DEG C ~ 1255 DEG C, and heat-up time is 190 ~ 240min.
6. manufacture method according to claim 5, is characterized in that, in described hot continuous rolling operation, it is 1065 DEG C ~ 1085 DEG C that roughing temperature out controls; Entry temperature at finishing is 1020 DEG C ~ 1040 DEG C, and exit temperature at finishing is 823 DEG C ~ 840 DEG C, and after finish rolling, the thickness of coiled sheet is 6.0mm ~ 10.0mm.
7. manufacture method according to claim 6, is characterized in that, in described section cooling operation, adopts leading portion cooling and the total length type of cooling, speed of cooling is 35 DEG C/and s ~ 55 DEG C/s; In described coiling process, coiling temperature is 560 DEG C ~ 580 DEG C.
8. manufacture method according to claim 2, it is characterized in that, in described steel making working procedure, RH vacuum-treat gained molten steel is grouped into by the one-tenth of following weight percent: 0.03% C, 0.08% Si, 1.80% Mn, 0.012% P, 0.003% S, 0.080% Nb, 0.12% Mo, 0.15% Ti, 0.0018% Ca, 0.034% Alt, and surplus is Fe and inevitable impurity; In described heating process, tapping temperature is 1255 DEG C; In described hot continuous rolling operation, exit temperature at finishing is 830 DEG C; In described section cooling operation, speed of cooling is 35 DEG C/s; In described coiling process, coiling temperature is 580 DEG C; The Ceq IIW of described finished product is 0.354, and yield strength is 780Mpa, and tensile strength is 850Mpa, and elongation after fracture is 19%.
9. manufacture method according to claim 2, it is characterized in that, in described steel making working procedure, RH vacuum-treat gained molten steel is grouped into by the one-tenth of following weight percent: 0.045% C, 0.11% Si, 1.82% Mn, 0.011% P, 0.0028% S, 0.075% Nb, 0.15% Mo, 0.155% Ti, 0.0025% Ca, 0.040% Alt, and surplus is Fe and inevitable impurity; In described heating process, tapping temperature is 1245 DEG C; In described hot continuous rolling operation, exit temperature at finishing is 840 DEG C; In described section cooling operation, speed of cooling is 45 DEG C/s; In described coiling process, coiling temperature is 565 DEG C; The Ceq IIW of described finished product is 0.378, and yield strength is 775Mpa, and tensile strength is 840Mpa, and elongation after fracture is 18%.
10. manufacture method according to claim 2, it is characterized in that, in described steel making working procedure, RH vacuum-treat gained molten steel is grouped into by the one-tenth of following weight percent: 0.05% C, 0.14% Si, 1.85% Mn, 0.013% P, 0.0025% S, 0.071% Nb, 0.18% Mo, 0.16% Ti, 0.0035% Ca, 0.038% Alt, and surplus is Fe and inevitable impurity; In described heating process, tapping temperature is 1240 DEG C; In described hot continuous rolling operation, exit temperature at finishing is 825 DEG C; In described section cooling operation, speed of cooling is 60 DEG C/s; In described coiling process, coiling temperature is 560 DEG C; The Ceq IIW of described finished product is 0.394, and yield strength is 840Mpa, and tensile strength is 915Mpa, and elongation after fracture is 17%.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107012287A (en) * | 2017-04-18 | 2017-08-04 | 攀钢集团攀枝花钢铁研究院有限公司 | Smelting process for heat stamping and shaping steel |
| CN107964624A (en) * | 2016-10-19 | 2018-04-27 | 上海梅山钢铁股份有限公司 | A kind of yield strength 500MPa level structure steel and preparation method thereof |
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| CN109735764A (en) * | 2019-01-17 | 2019-05-10 | 江苏利淮钢铁有限公司 | A kind of 800MPa grades of high-strength tenacity bainite vehicle crossbeam band steel and its production method |
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| CN107964624A (en) * | 2016-10-19 | 2018-04-27 | 上海梅山钢铁股份有限公司 | A kind of yield strength 500MPa level structure steel and preparation method thereof |
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| CN109182639A (en) * | 2018-09-13 | 2019-01-11 | 马鞍山钢铁股份有限公司 | A method of improving the high-strength automotive frame steel cleanness of 420MPa under no Calcium treatment process conditions |
| CN109182639B (en) * | 2018-09-13 | 2020-07-14 | 马鞍山钢铁股份有限公司 | Method for improving cleanliness of 420MPa high-strength automobile girder steel under calcium-free treatment process condition |
| CN109735764A (en) * | 2019-01-17 | 2019-05-10 | 江苏利淮钢铁有限公司 | A kind of 800MPa grades of high-strength tenacity bainite vehicle crossbeam band steel and its production method |
| CN110004854A (en) * | 2019-01-21 | 2019-07-12 | 北京中交畅观科技发展有限公司 | Three (A) grade degree of protection highway barriers of one kind and its manufacturing method |
| CN113106335A (en) * | 2021-03-11 | 2021-07-13 | 邯郸钢铁集团有限责任公司 | 800 MPa-grade high-strength weather-resistant girder steel belt and preparation method thereof |
| CN114480973A (en) * | 2022-01-28 | 2022-05-13 | 本钢板材股份有限公司 | Ultra-wide specification 800 MPa-level hot-rolled girder steel and production process thereof |
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